In article ,
"Vince Fiscus, KB7ADL" wrote:

Cut your antenna to the frequency or band of choice. Listen with the
balun in, then listen without it. I'll bet you won't be able to tell
a difference. In fact, there will even be a little loss in the
balun. The point I'm trying to make is, Cut your antenna to the
frequency you want for best performance and you won't need to waste
money and time building baluns.

I have done this and the Balun make a large difference in signal level
at the radio. There are many reasons for the improvement that a Balun
makes. Why would you think that it would not?

--
Telamon
Ventura, California

"Vince Fiscus, KB7ADL" wrote in
:

Michalkun wrote in
.251:

How does one can determine the impendance of a wire to get the right
balun for it, so it can be hooked up to the coaxial cable?



You don't say what kind of wire antenna you are using, but I don't
think I would worry about using a balun if you're just using the wire
antenna for receiving. If your antenna is a dipole, just connect the
wires straight to the coax. If you still want a balun, buy a one to
one balun for the dipole or just make a coax balun, coil seven to ten
turns of coax six inches in diameter. If your wire antenna is a loop
or folded dipole, you'll want a four to one balun.

And if you're reeeeally stuck on getting just the right balun, you
can find out what the impendence of your antenna is with an antenna
analyzer. MFJ make a cheap one, but I wouldn't waste the money buying
an analyzer just for a receive setup.

With the coax coiling where should I coil it, close to the antenna or close
to the radio? Do you have any idea how many coils give what ratio?

Y'all be trippin'. An MLB or a home made 9:1 UnUn does wonders for
reception across a very wide frequency range.

The device does 2 important things:

a] It prevents the source impedance from exceeding the load impedance,
(which is one rule that cannot ever be succesfully broken)

2] It places all parts of the antenna system at DC ground, preventing
static buildup and keeping the outer conductor from picking up
radiation

An antenna tuner is a big pain in the butt.

On Tue, 08 Jul 2003 06:52:59 -0600, JJ
wrote:



Mark S. Holden wrote:
"Vince Fiscus, KB7ADL" wrote:

Cut your antenna to the frequency or band of choice. Listen with the
balun in, then listen without it. I'll bet you won't be able to tell a
difference. In fact, there will even be a little loss in the balun.
The point I'm trying to make is, Cut your antenna to the frequency you
want for best performance and you won't need to waste money and time
building baluns.

KB7ADL



The typical SWL listens on several bands so they'd need more antennas.

I guestimate my cost for a 9:1 transformer at about $2. I probably spend about half an hour making and installing one.

You can't buy a remote RF switch or very much coax for $2.

Also, I find the ferrite greatly reduces RFI that is brought back to the antenna on the shield of the coax.

For receiving a balun is of little value. For a certain length of
antenna there is one wavelength that gives the ratio at which the
balun is designed for. When you go to different wavelengths then
the antenna shows a different impedance and the balun may do more
harm than good. The best bet for the SW listener who usually uses
a long wire antenna, is an antenna tuner to match the receiver to
varying impedances.

Michalkun wrote:


With the coax coiling where should I coil it, close to the antenna or close
to the radio? Do you have any idea how many coils give what ratio?

Save you time and energy, winding the coax into a few turns isn't
going to improve the reception of your antenna.

Dave wrote in message . ..
Balderdash. A transformer that correctly drives the co-ax is a great
advantage.

Depends on the radio. Very few modern radios would benefit as far as
s/n ratio.
All the transformer usually does is pump up the s meter. If when
hooking up the antenna, the noise level increases, you have enough
signal. Increasing the level does not increase the s/n ratio unless
the radio is half dead. On the lower frequencies, you have so much
signal level with any decent length wire, you could drastically reduce
it, and still have plenty.

On Mon, 07 Jul 2003 11:20:47 -0600, JJ
wrote:



Vince Fiscus, KB7ADL wrote:

There is no real advantage
for a balun on an antenna just for receiving.

Well, there is in some cases. In cases of bad shack noise, you can
drastically reduce noise ingress by adding a good balun or choke.
Also, many directional antennas like yagi's need decoupling for an
accurate pattern. Feedline radiation will skew the pattern. Also with
verticals used for VHF/UHF, decoupling is critical for good low angle
performance. Being all is reciprical, it's as important to receive as
it is to transmit. But, I do agree, as far as s/n ratio is concerned
with an HF wire antenna, a balun or transformer is not generally
needed. If adding matching actually improves the s/n ratio, you likely
have a fairly lame radio. The bigger payoff is reduced noise ingress
from the shack. That will improve the s/n ratio. If you actually have
noise that is... MK

In article ,
(Mark Keith) wrote:

Dave wrote in message
. ..
Balderdash. A transformer that correctly drives the co-ax is a
great advantage.

Depends on the radio. Very few modern radios would benefit as far as
s/n ratio. All the transformer usually does is pump up the s meter.
If when hooking up the antenna, the noise level increases, you have
enough signal. Increasing the level does not increase the s/n ratio
unless the radio is half dead. On the lower frequencies, you have so
much signal level with any decent length wire, you could drastically
reduce it, and still have plenty.

On Mon, 07 Jul 2003 11:20:47 -0600, JJ
wrote:



Vince Fiscus, KB7ADL wrote:

There is no real advantage
for a balun on an antenna just for receiving.

Well, there is in some cases. In cases of bad shack noise, you can
drastically reduce noise ingress by adding a good balun or choke.
Also, many directional antennas like yagi's need decoupling for an
accurate pattern. Feedline radiation will skew the pattern. Also with
verticals used for VHF/UHF, decoupling is critical for good low angle
performance. Being all is reciprical, it's as important to receive as
it is to transmit. But, I do agree, as far as s/n ratio is concerned
with an HF wire antenna, a balun or transformer is not generally
needed. If adding matching actually improves the s/n ratio, you
likely have a fairly lame radio. The bigger payoff is reduced noise
ingress from the shack. That will improve the s/n ratio. If you
actually have noise that is... MK


I don¹t understand this kind of thinking that you should not derive the
maximum benefit of an antenna that one has gone through the trouble to
put up. Your logic of all the transformer is good for is pumping up the
S meter falls flat when you don¹t have enough signal for full quieting
or whether you can make out the program material at all if the signal is
very weak. I don¹t see the need to call anyone¹s radio lame either.

Most antennas output impedance is nowhere near the typical 50-ohm coax
and a transformation can remedy that. In addition there are advantages
to preventing the coax interacting with the antenna some of which you
stated above.

Some antenna designs are better at rejecting local noise than others.
They only work if coupled properly to the coax resulting in better
signal to noise.

--
Telamon
Ventura, California

Michalkun wrote:

How does one can determine the impendance of a wire to get the right balun
for it, so it can be hooked up to the coaxial cable?

Check out the following website for how to build an 'inverted-L'
shortwave antenna with a *properly* installed balun. This design can
make a big difference in reducing local (man made) noise on your
antenna, which makes it easier to hear weak stations. I used R6U coax
which is made for satellite TV systems. It's 75-ohm (not 50-ohm) but
that's close enough for shortwave receiving antennas. I made the balun
on a T-34 ferrite core. You can get these cores from 'Amidon' or one of
their dealers.

http://www.anarc.org/naswa/badx/ante...e_antenna.html


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In article ,
Michalkun wrote:

How does one can determine the impendance of a wire to get the right balun
for it, so it can be hooked up to the coaxial cable?

The impedance of the wire will depend on:

1. The diameter of the wire. The larger the diameter (smaller AWG
number) the lower the impedance will be.

2. The height of the wire above ground. The higher the wire the higher
the impedance will be.

3. The ground conductivity. The more conductive the ground the lower
the impedance will be. Also note here that this is affected by how the
antenna is grounded. If you have just a ground stake or whether you have
radials will make a big difference on how well the wire will perform.
The poorer the ground conductivity the more how you provide grounding
will determine how well the wire will work.

Why grounding is so important is because the wire is just half the
antenna with the ground being the other half. You have to give the RF
some place to go to complete the circuit that is your antenna or it
will not work well.

The coax back to your radio can be that ground but that has the
disadvantage of mixing the antenna currents with the power line noise
at the radios location reducing the signal to noise. One reason why
people are advocates of Baluns is because the antenna can have its own
ground independent of the radio ground.

For a wire antenna one radial run directly under the antenna wire will
do the most good as a minimalist approach.

All that being said a typical wire will be something in the 400 to 600
hundreds of ohms range so the 9 to 1 type of transformer would be the
best type.

--
Telamon
Ventura, California

Telamon wrote in message


I don¹t understand this kind of thinking that you should not derive the
maximum benefit of an antenna that one has gone through the trouble to
put up. Your logic of all the transformer is good for is pumping up the
S meter falls flat when you don¹t have enough signal for full quieting
or whether you can make out the program material at all if the signal is
very weak. I don¹t see the need to call anyone¹s radio lame either.

If you are using a 70 ft random wire on HF, and you don't have enough
signal level to have a usable s/n ratio on any HF freq, you would have
a lame radio. Thats just the simple facts. Nothing personal... This is
2003. Radios are not half dead on the upper bands like to used to be
50 years ago, unless they are toys or out of alignment. There is no
"full quieting" unless you are on FM. That would generally be 10m up.
I'll repeat it again. If you hook up your antenna, and the background
noise level increases, even if just a little, you have all the s/n
ratio you need. Increasing the signal level beyond that point will not
increase the s/n ratio. It only pumps up the S meter. To see an
improvement in copy , you would need to use a directive antenna. Any
noise along with the desired signal has also increased in proportion,
so your actual s/n ratio is the same.
Sure, the signal may sound "louder" with the higher S meter reading,
but thats mainly because the level is higher, and due to the
limitations of the filter, the signal seems "wider". But the
selectivity has slightly decreased.

Most antennas output impedance is nowhere near the typical 50-ohm coax
and a transformation can remedy that.

But it doesn't matter. You don't have enough loss with the mismatch to
worry about with any decent radio. It's just not enough to knock you
out of the water. I did the math on this a few months ago, and posted
here to demonstrate this. This has been debated before many times. I
used coax feed with wild feedpoint impedances just to ensure a worst
case as far as feeder loss. It doesn't amount to enough to hurt you.
If it does, you have a lame radio. If you used a random wire direct
with no feeder, there is even less loss. For receiving, the mismatch
in that case doesn't matter enough to worry about at all.

In addition there are advantages
to preventing the coax interacting with the antenna some of which you
stated above.

Some antenna designs are better at rejecting local noise than others.
They only work if coupled properly to the coax resulting in better
signal to noise.

Sure, but that has nothing to do with the impedance tranformation. I
have no problems if people want to use transformers, I'm just saying
it's an option and should not really be needed as far as s/n ratio is
concerned. I don't use a tuner or matching on my wire antenna no
matter what freq I go to. I don't need to. I don't even come close to
needing it. I have plenty of signal level on any freq. Any doubt's and
you can pick a freq, and I'll record it and post as an mpeg.
I can dial up 28 mhz at 3 AM, and have plenty of background noise. If
I switch to the dummy load, all goes dead. Actually, I bet I could do
it at 150 mhz also...Sure, I can add my MFJ-989c tuner, and get a
perfect match as far as my radio is concerned, and maybe even pump up
the noise level an s unit or two. But it doesn't increase my s/n ratio
one whit.
BTW, any radio can be a "lame" radio, if it's not working right. I've
had a few of mine cramp up through the years. MK

In article ,
(Mark Keith) wrote:

Telamon wrote in message

I don¹t understand this kind of thinking that you should not derive the
maximum benefit of an antenna that one has gone through the trouble to
put up. Your logic of all the transformer is good for is pumping up the
S meter falls flat when you don¹t have enough signal for full quieting
or whether you can make out the program material at all if the signal is
very weak. I don¹t see the need to call anyone¹s radio lame either.

If you are using a 70 ft random wire on HF, and you don't have enough
signal level to have a usable s/n ratio on any HF freq, you would
have a lame radio. Thats just the simple facts. Nothing personal...
This is 2003. Radios are not half dead on the upper bands like to
used to be 50 years ago, unless they are toys or out of alignment.
There is no "full quieting" unless you are on FM. That would
generally be 10m up. I'll repeat it again. If you hook up your
antenna, and the background noise level increases, even if just a
little, you have all the s/n ratio you need. Increasing the signal
level beyond that point will not increase the s/n ratio. It only
pumps up the S meter. To see an improvement in copy , you would need
to use a directive antenna. Any noise along with the desired signal
has also increased in proportion, so your actual s/n ratio is the
same. Sure, the signal may sound "louder" with the higher S meter
reading, but thats mainly because the level is higher, and due to the
limitations of the filter, the signal seems "wider". But the
selectivity has slightly decreased.

The signal will not sound louder with a higher S meter reading if you
are using a radio with AGC on and it¹s working right.

Sorry to use a miss leading term ³full quieting.² I did not mean to
refer to FM modulation. Let me explain that I live in town and have
local noise to compete with any signal I pick up. This noise must be
overcome so I only hear the program material of interest. In other words
the volume can be turned up so the program material is very loud without
any background noise or hiss. Antenna efficiency that generates more
signal energy overcomes the local noise sources. You must be unusually
lucky to live in a location where all you pick up is either broadcast
signal or atmospheric noise. I don¹t think most people are as fortunate.

Most antennas output impedance is nowhere near the typical 50-ohm coax
and a transformation can remedy that.

But it doesn't matter. You don't have enough loss with the mismatch to
worry about with any decent radio. It's just not enough to knock you
out of the water. I did the math on this a few months ago, and posted
here to demonstrate this. This has been debated before many times. I
used coax feed with wild feedpoint impedances just to ensure a worst
case as far as feeder loss. It doesn't amount to enough to hurt you.
If it does, you have a lame radio. If you used a random wire direct
with no feeder, there is even less loss. For receiving, the mismatch
in that case doesn't matter enough to worry about at all.

Well OK I guess my radios are lame or busted. I must be imagining things
when signals go from ³I can just make it out S1² to ³easy to listen to
S3² on the folded dipole with the transformer. My other loop antennas
must not be working right either.

In addition there are advantages to preventing the coax interacting
with the antenna some of which you stated above.

Some antenna designs are better at rejecting local noise than
others. They only work if coupled properly to the coax resulting in
better signal to noise.

Sure, but that has nothing to do with the impedance tranformation. I
have no problems if people want to use transformers, I'm just saying
it's an option and should not really be needed as far as s/n ratio is
concerned. I don't use a tuner or matching on my wire antenna no
matter what freq I go to. I don't need to. I don't even come close to
needing it. I have plenty of signal level on any freq. Any doubt's
and you can pick a freq, and I'll record it and post as an mpeg. I
can dial up 28 mhz at 3 AM, and have plenty of background noise. If I
switch to the dummy load, all goes dead. Actually, I bet I could do
it at 150 mhz also...Sure, I can add my MFJ-989c tuner, and get a
perfect match as far as my radio is concerned, and maybe even pump up
the noise level an s unit or two. But it doesn't increase my s/n
ratio one whit. BTW, any radio can be a "lame" radio, if it's not
working right. I've had a few of mine cramp up through the years.

I¹ll see about getting my radios fixed.

--
Telamon
Ventura, California